This present invention relates to assemblies of a viewer and viewable material such as maps or like visually depicted information such as route guides. It extends further for example to viewing of handbook information, charts or cable-management diagrams. For convenience the invention will be described with reference to maps.
It is commonplace to present maps, that is to say stylised area representations of a tract of terrain or complex routes, in the form of a large sheet of paper or like material covering a large area and containing a great deal of information. Typically, because of their large size these sheets are rolled or folded. If the maps are to be used indoors, for example for planning or teaching purposes, the nature of the sheet is of secondary importance since it is readily capable of being unrolled or unfolded to the extent desired to give the immediately relevant information, and kept in that state. However, very frequently maps are intended to be read out of doors as part of some sporting or other activity. For example, in addition to the maps and route guides e.g. subway guides generally utlized by tourists or other travellers, skiers need to consult piste maps, orienteers need maps of the topography and utilization of countryside, and glider pilots or partakers in like aerial sports need some form of map consultation. It is common, therefore, to provide maps at different scales and to emphasise different features. Indeed, some maps are provided as route indicators showing in a more or less elongated form the features of a desired route but not showing associated countryside (to any great extent) at either side of the route.
One problem common to the consultation of maps outdoors concerns the convenient manipulation of the maps. Typically, for example, a skier who is warmly clothed against the temperature and is wearing gloves and carrying the usual ski poles finds it difficult to open the map and fold it to the relevant part. He has to remove his gloves, and having no suitable pockets in the suit, typically hold them under one arm or in a similarly inconvenient position while he attempts to unfold and refold the map to a suitable location. If there is any sort of wind or like condition this can be a very difficult feat, and must of course be carried out again in reverse prior to actually commencing the descent. Such problems arise with hikers, orienteers, mountainers, gliders, hang-gliders, and in a wide range of other sports. Similar problems also arise in military use of maps, and the problem is compounded by the fact that the back of a conventional map is usually white in color and thus, if held up while the map is perused, is visible over long distances as a target for enemy fire.
Tourist maps also can be inconvenient for use, and their use is indicative of unfamiliarity with the locality, attracting fraud or theft.
Moreover, there is often the requirement for consultation of maps at night, using some form of torch or the like; military uses or night emergency services often require such a facility.
Other difficulties arise when using maps or charts in confined spaces e.g. underground or in cable ducting.
There is thus a requirement to provide maps or like information for occasional consultation in a convenient fashion over a range of outdoor map-using activities.